1. Field of the Invention
The present invention relates in general to a display device for providing or displaying a color image of an object, and more particularly to a technique for effecting high-quality reproduction of colors on the surface of the object.
2. Discussion of the Prior Art
It is useful to display an image of a desired object on a graphic display device, with high color reproduction quality. In designing a motor vehicle, for example, it is necessary to recognize an appearance of the motor vehicle as observed by human eyes. In this case, the color of the vehicle is an important factor.
However, the color of a motor vehicle as perceived by the human eyes varies with the environment in which the vehicle exists. For example, the color of a vehicle painted in a given color, as observed in one region of the earth, differs from that as observed in another region. The amounts of oxygen, ozone, water vapor and other components contained in the atmosphere vary depending upon the position on the earth. Accordingly, the spectral distribution of the natural or solar radiation incident upon the motor vehicle, and that of the radiation reflected from the vehicle, differ from one place to another, causing a difference or variation in the color of the vehicle as perceived by the human eyes.
In view of the above fact, one conventional practice to evaluate the color of a motor vehicle by a vehicle designer is to carry differently colored specimens of the vehicle to various places on the earth, and examine the specimens for the colors as observed in those places, or take color pictures of the specimens for examination by the designer.
The above approach suffers from a considerably large expense for transporting the vehicle specimens painted in many different colors to the various places on the earth, for local chromatic examination of the specimens. Moreover, the expense for this type of examination further increases if it is desired to check a variation in the human-perceived color of the vehicle which occurs depending upon the specific weather and time in the different global places, which also affect the spectral distribution or composition of the radiation incident upon the vehicle. Namely, the observers in the different places must wait until desired weather conditions are satisfied at different times.
Some motor vehicles are designed for use in a relatively limited global area. In this case, too, the chromatic examination of the vehicles must be effected under different weather conditions and at different times. Even in the same area, the spectral distribution of the radiation incident upon the vehicles varies from one local place to another, depending upon whether the atmosphere is clear or contaminated. Thus, the chromatic examination of a vehicle in one area on the earth requires a considerable expense.
The above problem also exists with outdoor ornamental objects, clothes, and many other objects than the motor vehicles, for which the color is an important factor.
Although the outdoor chromatic variation due to a change in the spectral distribution of the natural or sky radiation is comparatively significant, it is sometimes necessary to effect the indoor chromatic examination of furnitures and other indoor ornamental objects, whose colors as perceived by the observer vary with the nature of artificial radiations for indoor lighting.
To examine the variation in the color of an object due to a change in the spectral distribution of a radiation incident upon the object, it is effective to use a device which is capable of displaying color images of the object under different lighting conditions involving different spectral distributions of the incident radiation. However, such a color graphic display device is not known. A color graphic display device capable of color image reproduction according to display data representative of a color image of an object is presently available. Although this color graphic display device permits the color of the displayed image to be changed by changing the display data, it is not capable of providing an image of an object with high color reproduction quality, depending upon a specific radiation incident upon the object, and a surface condition of the object.